ASU researchers develop tiny lasers to speed computing

Researchers at Arizona State University have worked for years developing a tiny laser invisible to the naked eye.

See if you can spot the nanolaser at an ASU engineering lab. Hint: it's 1/100 the width of a human hair. (Photo by Nick Blumberg - KJZZ)

It used to give off so much heat that it had to operate in conditions 10 times colder than the Arctic, but
the nanolaser is one step closer to impacting devices we use every day.

What do you think of when you think of a laser? Maybe a futuristic weapon, like a blaster in "Star Wars?" Or maybe you have another image in your mind’s eye, an ominous presence, threatening to cut 007 in half.

The laser we are talking about isn’t quite so dramatic. For starters, it does not make a noise much more intimidating than the click of power button, and it is not exactly a weapon. This laser is more likely to speed up your computer than slice you in half, more on that later.

What’s probably the coolest part is that it’s small. Really small.

“One micron," said Cun-Zheng Ning, who leads ASU’s nanolaser project. “Which means if you put a hundred of our nanolasers together, the total length would be just like the thickness of a human hair.”

Ning has five nanolasers set up on a chip that you can only see with a microscope hooked up to a computer screen. The light it gives off is invisible to humans.

At first it looks like the chip is the size of an SD card, like you might put in your camera, but that is not the case. It is just the platform the chip rests on, while the actual chip is just about the size of the head of a pin.

The chamber that houses five nanolasers, with a camera hovering over it. (Photo by Nick Blumberg - KJZZ)

The lasers sit in this chamber that’s about as big around as a CD. In the past, Ning could only run the lasers if the chamber was cooled way down.

“At the beginning, of course, the device operated [at a] very low temperature, a few Kelvin," Ning said.

It's about 450 degrees below zero.

That was when they used liquid helium to cool the chamber. Eventually, they were able to move to liquid nitrogen, which isn’t quite as cold, a balmy 330 degrees below.

Now, ASU has finally developed an electrically powered nanolaser that can run at room temperature.

Kang Ding is a PhD student who has worked on this project for years and has seen some frustrating times.

“Yeah, the beginning of this story is very sad," Ding laughed. "We spent hours in the lab and we cannot get anything. But then, the more effort we put [in] we finally can get something.”

Ding said a lot of work went into fabricating the device properly. A tiny mistake when making an ordinary-sized device probably won’t affect much, but a tiny mistake when making a device smaller than a human hair is actually a huge mistake.

So, operating an electrically-powered nanolaser at room temperature is a breakthrough and all, but what could it actually do? Take a computer for example. It’s made up of multiple components, the cache, the memory, often multiple processors. All those components need to communicate with each other.

Ning said instead of sending signals over copper wires, nanolasers sending that information using light would be exponentially faster.

A magnified view of a silver-coated chip that holds five nanolasers. (Photo by Nick Blumberg - KJZZ)

Now that nanolasers have made it this far, researchers hope other, complementary fields will start to take notice and figure how else to apply these devices.

“I think there is a lot of interesting science and engineering and technology development that needs to be done," said Shaya Fainman, who leads the nanolaser team at UC San Diego.

He said they’re not competing with ASU, even if they are, it seems like a pretty friendly competition. Fainman’s less concerned with beating anyone than he is with nanolasers getting attention from the right kinds of people.

“One thing, maybe... I hate saying it that blunt, but I think that some of the funding agencies could look at this specific field a little bit more and make some focused programs," Fainman said.

In other words, no money, no super-fast, super-tiny, super-computers.

And even though he’s excited about this breakthrough, Cun-Zheng Ning knows there are still many hurdles to getting nanolasers in our phones or computers.

But, hey, who knows exactly how long it’ll be. In just a few years, nanolasers went from concept to reality, about as long as it took cell phones to go from a one-function block to something that can remind you to put the gazpacho on ice in an hour.

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